For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measure...For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measurements from multiple load/current conditions,and the estimation is relying on the accuracy of saturation model and other machine parameters in the model.Speed harmonic produced by harmonic currents is inductance-dependent,and thus this paper explores the use of magnitude and phase angle of the speed harmonic for accurate inductance estimation.Two estimation models are built based on either the magnitude or phase angle,and the inductances can be from d-axis voltage and the magnitude or phase angle,in which the filter influence in harmonic extraction is considered to ensure the estimation performance.The inductances can be estimated from the measurements under one load condition,which is free of saturation model.Moreover,the inductance estimation is robust to the change of other machine parameters.The proposed approach can effectively improve estimation accuracy especially under the condition with low current magnitude.Experiments and comparisons are conducted on a test PMSM to validate the proposed approach.展开更多
This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is math...This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.展开更多
For permanent magnet synchronous machines(PMSMs),accurate machine model is critical for high performance maximum torque per ampere(MTPA)control.However,as motor speed increases,the nonlinearity such as core loss effec...For permanent magnet synchronous machines(PMSMs),accurate machine model is critical for high performance maximum torque per ampere(MTPA)control.However,as motor speed increases,the nonlinearity such as core loss effect will affect the accuracy of machine model and thus the performance of online MTPA control.This paper firstly investigates the performance of the model based MTPA control under different motor speeds through modeling,simulation and experiments,which indicates that the accuracy of MTPA control is greatly reduced especially under high-speeds due to machine nonlinearity.Hence,this paper proposes an efficient nonlinearity compensation model based on polynomial fitting to model and compensate the MTPA error as motor speed increases.Considering both core loss and magnetic saturation effects,the compensation model is a nonlinear polynomial of speed and stator current.To obtain the fitting data,a derivative modeling method is proposed to compute the actual and detected MTPA angles under different speeds,in which the derivative model of torque to current ratio is fitted and the MTPA angle is obtained by setting the derivative model to zero.The proposed compensation model is both computation effective and easy to use for MTPA control,as it computes the compensation term that can be directly combined to other model-based methods.The proposed model is evaluated with experiments and comparisons on a test motor to show the performance improvement.展开更多
For permanent magnet synchronous machine(PMSM),the machine model is critical to predict the operating states for motor control,which,however,can be greatly affected by system nonlinearities.Hence,this paper investigat...For permanent magnet synchronous machine(PMSM),the machine model is critical to predict the operating states for motor control,which,however,can be greatly affected by system nonlinearities.Hence,this paper investigates accurate machine modeling for control and parameter estimation.In the proposed approach,the PMSM model with saturated inductances is used as the base model,and this paper investigates modeling and compensation of the offsets to the base model due to system nonlinearities such as saturation and core loss effects for accurate machine modeling and voltage prediction.Specifically,the offsets to the base model are modeled using nonlinear functions with variable coefficients to compensate saturation and core loss effect,which can achieve better accuracy without changing the model structure.A differential estimation model is derived to estimate the model coefficients from a small amount of measurements with simplified procedure.Moreover,the model offset calculation is both computation and memory efficient with simplified implementation.The contribution is to improve the machine model accuracy and achieve precise voltage prediction for practical applications.Experiments,comparisons and the application to temperature estimation are conducted on a test interior PMSM to validate the proposed approach.展开更多
Objective:To conduct a meta-analysis assessing the perioperative,functional and oncological outcomes of partial nephrectomy(PN)and radical nephrectomy(RN)for T1b tumours.The primary endpoints were the oncological outc...Objective:To conduct a meta-analysis assessing the perioperative,functional and oncological outcomes of partial nephrectomy(PN)and radical nephrectomy(RN)for T1b tumours.The primary endpoints were the oncological outcomes.The secondary endpoints were the perioperative and functional outcomes.Methods:A systematic literature review was performed by searching multiple databases through February 2019 to identify eligible comparative studies according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement.Identified reports were assessed according to the Newcastle-Ottawa Scale for nonrandomized controlled trials.Results:Overall,13 retrospective cohort studies were included in the analysis.Patients undergoing PN were younger(weighted mean difference[WMD]3.49 years,95%confidence interval[CI]5.16 to1.82;p<0.0001)and had smaller masses(WMD0.45 cm,95%CI0.59 to0.31;p<0.0001).There were no differences in the oncological outcome,which was demonstrated by progression-free survival(hazard ratio[HR]0.70;pZ0.22),cancerspecific mortality(HR 0.91;pZ0.57)and all-cause mortality(HR 1.01;pZ0.96).The two procedures were similar in estimated blood loss(WMD16.47 mL;pZ0.53)and postoperative complications(risk ratio[RR]1.32;pZ0.10),and PN provided better renal function preservation and was related to a lower likelihood of chronic kidney disease onset(RR 0.38;pZ0.006).Conclusion:PN is an effective treatment for T1b tumours because it offers similar surgical morbidity,equivalent cancer control,and better renal preservation compared to RN.展开更多
Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understa...Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understand the pathogenesis of the disease,activities of superoxide dismutase(SOD),catalase(CAT),and level of malondialdehyde(MDA)in coelomic fluid were detected using the Assay Kit and metabolites in the body wall were assessed using ultra-performance liquid chromatography and quadrupole-time of flight mass spectrometry.The results indicated that level of MDA was increased during SUS compared with healthy individuals(P<0.01),but activities of SOD and CAT were reduced(P<0.05).In metabolomics analysis,metabolites,such as adenosine,choline,betaine aldehyde,palmitic acid,and taurine,were found to be upregulated and 2-oxoadipic acid,anthranilic acid(vitamin L1),thioetheramide-PC,cholesterol-3-sulfate,and pentadecanoic acid were downregulated(VIP>1 and P<0.1).Pathway enrichment analysis indicated most enrichment of KEGG pathways were mainly related to energy metabolism,immunity,and osmoregulation such as ABC transporters,glycine,serine and threonine metabolism,tryptophan metabolism and neuroactive ligand-receptor interaction.Our study reflected the difference in enzyme activity and metabolites between A.japonicus with SUS and those without,which will provide reference data for investigating SUS.展开更多
Uncoupling protein 2 (UCP2) is a proton transporter located in the inner mitochondrial membrane, and inhibits the formation of adenosine triphosphate and reactive oxygen species by uncoupling oxidative phosphorylation...Uncoupling protein 2 (UCP2) is a proton transporter located in the inner mitochondrial membrane, and inhibits the formation of adenosine triphosphate and reactive oxygen species by uncoupling oxidative phosphorylation. To provide a theoretical basis for the role of SiUCP2 in lipid metabolism, a 2 341-bp full-length cDNA of SiUCP2 from sea urchin Strongylocentrotus intermedius , which encodes 323 amino acids (predicted MW 36.11 kDa) was obtained, and the structure and function of the SiUCP2 gene and its expression at the mRNA and protein level were studied. SiUCP2 had high homology with UCP2 of other species. Expression of SiUCP2 was detected in the order of tube feet > gonads > coelomocytes > intestines. The expression level was the highest in prismatic larvae and lowest in the two-cell stage. Moreover, using in-situ hybridization, we found that SiUCP2 protein was expressed in the gonads and intestine. This study provided a theoretical basis for subsequent studies on the role of SiUCP2 and its regulatory mechanism in lipid metabolism, and for the improvement of gonad quality to obtain a higher economic value from sea urchins.展开更多
基金supported in part by the National Natural Science Foundation of China(62473387)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP241)the Department of Science and Technology of Guangdong Province(2021QN020085)。
文摘For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measurements from multiple load/current conditions,and the estimation is relying on the accuracy of saturation model and other machine parameters in the model.Speed harmonic produced by harmonic currents is inductance-dependent,and thus this paper explores the use of magnitude and phase angle of the speed harmonic for accurate inductance estimation.Two estimation models are built based on either the magnitude or phase angle,and the inductances can be from d-axis voltage and the magnitude or phase angle,in which the filter influence in harmonic extraction is considered to ensure the estimation performance.The inductances can be estimated from the measurements under one load condition,which is free of saturation model.Moreover,the inductance estimation is robust to the change of other machine parameters.The proposed approach can effectively improve estimation accuracy especially under the condition with low current magnitude.Experiments and comparisons are conducted on a test PMSM to validate the proposed approach.
基金supported in part by the National Natural Science Foundation of China under Grant 52105079 and 62103455。
文摘This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.
基金supported by in part by the National Natural Science Foundation of China(62473387,52105079,62103455)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP241)。
文摘For permanent magnet synchronous machines(PMSMs),accurate machine model is critical for high performance maximum torque per ampere(MTPA)control.However,as motor speed increases,the nonlinearity such as core loss effect will affect the accuracy of machine model and thus the performance of online MTPA control.This paper firstly investigates the performance of the model based MTPA control under different motor speeds through modeling,simulation and experiments,which indicates that the accuracy of MTPA control is greatly reduced especially under high-speeds due to machine nonlinearity.Hence,this paper proposes an efficient nonlinearity compensation model based on polynomial fitting to model and compensate the MTPA error as motor speed increases.Considering both core loss and magnetic saturation effects,the compensation model is a nonlinear polynomial of speed and stator current.To obtain the fitting data,a derivative modeling method is proposed to compute the actual and detected MTPA angles under different speeds,in which the derivative model of torque to current ratio is fitted and the MTPA angle is obtained by setting the derivative model to zero.The proposed compensation model is both computation effective and easy to use for MTPA control,as it computes the compensation term that can be directly combined to other model-based methods.The proposed model is evaluated with experiments and comparisons on a test motor to show the performance improvement.
基金supported by in part by the National Natural Science Foundation of China(52105079,62103455)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP241)。
文摘For permanent magnet synchronous machine(PMSM),the machine model is critical to predict the operating states for motor control,which,however,can be greatly affected by system nonlinearities.Hence,this paper investigates accurate machine modeling for control and parameter estimation.In the proposed approach,the PMSM model with saturated inductances is used as the base model,and this paper investigates modeling and compensation of the offsets to the base model due to system nonlinearities such as saturation and core loss effects for accurate machine modeling and voltage prediction.Specifically,the offsets to the base model are modeled using nonlinear functions with variable coefficients to compensate saturation and core loss effect,which can achieve better accuracy without changing the model structure.A differential estimation model is derived to estimate the model coefficients from a small amount of measurements with simplified procedure.Moreover,the model offset calculation is both computation and memory efficient with simplified implementation.The contribution is to improve the machine model accuracy and achieve precise voltage prediction for practical applications.Experiments,comparisons and the application to temperature estimation are conducted on a test interior PMSM to validate the proposed approach.
文摘Objective:To conduct a meta-analysis assessing the perioperative,functional and oncological outcomes of partial nephrectomy(PN)and radical nephrectomy(RN)for T1b tumours.The primary endpoints were the oncological outcomes.The secondary endpoints were the perioperative and functional outcomes.Methods:A systematic literature review was performed by searching multiple databases through February 2019 to identify eligible comparative studies according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement.Identified reports were assessed according to the Newcastle-Ottawa Scale for nonrandomized controlled trials.Results:Overall,13 retrospective cohort studies were included in the analysis.Patients undergoing PN were younger(weighted mean difference[WMD]3.49 years,95%confidence interval[CI]5.16 to1.82;p<0.0001)and had smaller masses(WMD0.45 cm,95%CI0.59 to0.31;p<0.0001).There were no differences in the oncological outcome,which was demonstrated by progression-free survival(hazard ratio[HR]0.70;pZ0.22),cancerspecific mortality(HR 0.91;pZ0.57)and all-cause mortality(HR 1.01;pZ0.96).The two procedures were similar in estimated blood loss(WMD16.47 mL;pZ0.53)and postoperative complications(risk ratio[RR]1.32;pZ0.10),and PN provided better renal function preservation and was related to a lower likelihood of chronic kidney disease onset(RR 0.38;pZ0.006).Conclusion:PN is an effective treatment for T1b tumours because it offers similar surgical morbidity,equivalent cancer control,and better renal preservation compared to RN.
基金Supported by the National Natural Science Foundation of China(No.31772849)the Scientific Research Funding Project of Liaoning Provincial Department of Education in 2019(No.DL201901)the Program for Liaoning Innovative Research Team in University(No.LT2019003)。
文摘Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understand the pathogenesis of the disease,activities of superoxide dismutase(SOD),catalase(CAT),and level of malondialdehyde(MDA)in coelomic fluid were detected using the Assay Kit and metabolites in the body wall were assessed using ultra-performance liquid chromatography and quadrupole-time of flight mass spectrometry.The results indicated that level of MDA was increased during SUS compared with healthy individuals(P<0.01),but activities of SOD and CAT were reduced(P<0.05).In metabolomics analysis,metabolites,such as adenosine,choline,betaine aldehyde,palmitic acid,and taurine,were found to be upregulated and 2-oxoadipic acid,anthranilic acid(vitamin L1),thioetheramide-PC,cholesterol-3-sulfate,and pentadecanoic acid were downregulated(VIP>1 and P<0.1).Pathway enrichment analysis indicated most enrichment of KEGG pathways were mainly related to energy metabolism,immunity,and osmoregulation such as ABC transporters,glycine,serine and threonine metabolism,tryptophan metabolism and neuroactive ligand-receptor interaction.Our study reflected the difference in enzyme activity and metabolites between A.japonicus with SUS and those without,which will provide reference data for investigating SUS.
基金Supported by the National Key Research and Development Program of China(No.2018YFD0901601)Chinese Outstanding Talents in Agricultural Sciences(for Yaqing CHANG)。
文摘Uncoupling protein 2 (UCP2) is a proton transporter located in the inner mitochondrial membrane, and inhibits the formation of adenosine triphosphate and reactive oxygen species by uncoupling oxidative phosphorylation. To provide a theoretical basis for the role of SiUCP2 in lipid metabolism, a 2 341-bp full-length cDNA of SiUCP2 from sea urchin Strongylocentrotus intermedius , which encodes 323 amino acids (predicted MW 36.11 kDa) was obtained, and the structure and function of the SiUCP2 gene and its expression at the mRNA and protein level were studied. SiUCP2 had high homology with UCP2 of other species. Expression of SiUCP2 was detected in the order of tube feet > gonads > coelomocytes > intestines. The expression level was the highest in prismatic larvae and lowest in the two-cell stage. Moreover, using in-situ hybridization, we found that SiUCP2 protein was expressed in the gonads and intestine. This study provided a theoretical basis for subsequent studies on the role of SiUCP2 and its regulatory mechanism in lipid metabolism, and for the improvement of gonad quality to obtain a higher economic value from sea urchins.
